System of electrical distribution.



E. F. W. ALEXANDERSON. SYSTEM 0F ELECTRICAL msmauxdiv.

APPLICATION FILED )UNE X9, 91.

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EENS?? I?. 'Wi LEXITDERSON, DE SCEEEENECBTADY, NEVI "YORK", ASSIGNOR TG GENERAL ELECTRC CMPANZ, A CRPORTGN OF NEW' YORK.

SYSTEM 0F ELECTRCAL' DESTRBUT'IGN.

Specification of Letters a'cent.

satelites sew. is, 1ers.

.hpplicaticn filed. Enne 19, 1911. Serial No. 664,062.

1 'o ZZ 'fc/ioni. t may concern Be it known that l, ERNST l". .7. ALEXAN- nnsson, a citizen of the 4United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful improvements in Systems of Electrical Distribution, o which the iolimving is a specification.

My invention relates to systems of eiectrical distribution and has for its object en improved method and means of utilizing' a singie phase source of alternating curreiit for i supplying a polyphsse load.

it is Welllrnon'n thatl a single phase alternating current may he converted intov a polyphase alternating current hy means of a suitable phase'converter which may he con structed like polyphase induction motor, one of the pi ases being connected to the singlo phase source of supply hand the other phase or phases 'to the polyphase load. Such an arrangement' is shown vhy rey previous Patent, No. 901,513, this patent showing various improvements for obtaining' better haicncing of the polyphase voltages.

My present invention' relates to an iinproved arrangement for balancing the poly phase voltages in a system employing phase converter, i accomplish the obj-ect of my invention by connecting one ot' the phases of the converter to the single phase source of supply and in series with one of the phases of the load, connecting the other phase or if desired the other phases of the converter to another phsse orphises of the load, and interpoiating into the last mei'itioned phase circuit or circuits s voltage different in velue l from that of the source.

The novel features of my invention are l pointed out with moreparticularity in the claims appended to and made s part of this speciication.

For a further understanding of my invention, reference may be made to the accompanying dravvings, Wherein- I Figure l shows diagrammatically my ii1-\ll vvention applied ton the operation of two induction motors; 2 shows diagrammatieeiiy the scheme ci connections Whlch I einpioy, and Figs. and 5 are explanatory vector diagrams. v

TSWhile Y Y l d' my intention may ce app led to a polyp-hase loud which may he ay form ofI trsnslating device und of any number of application to a two phase or quarter phase leed consisting of inductionmotors, and I sha-ll therefore describe my invention as applied to such, hut it will he understoodI that it may he applied to any forni of .loa-d of any desired number of phases.

I will first refer to Fig. 2, Where li have shown diagrammatically a two-phase induction motor and a two-phase phase converter connected according to my invention. Across the mains l, 2, supplied 'With single-phase current from any suitable source, I connect a" 1compensator` or transformer 7 and one phase 3 of the primary Winding of the phase converter in series with one phase 5 of the primary Winding ofthe induction motor. Associated with the phase 3 vis another phase Il of the primary Winding of the converter, which, together with the usual secondary windin-lr, not shown, goes to make up a phase converter ot any Well known type. Similarly, the phase 6 constitutes the other primary winding of a quarter-phase induction motor Whose secondary is not shown. The phases and 6 are connected in series hetwecn the mein 2 and an intermediate point 8 of the compensator 7.

lt will he noticed that one of the phases of the converter is connected with the our-ce and in series with one of the phases of 'the load or induction motor to be operited and that thelsecond phase l of the converter is connected to the second phase 6 of the load or induction motor and that preterahly into this phase circuit is interpolated a voltage which is a portion of the voltage from the source, this voltage being interpolated in the arrangement shown in this tlgure by connecting one end of phase 4 of the conyertcr to conductor 2 and by connecting the end of'phzise Winding- 6 of the load or induction motor not connected to the converter to point 8 of compensator 7. For convenience of explanation, I shall call phases 3 and, 5 of the converter and motor respectively, that are shown as connected in series and direct-ly across conductors l and 2 respectively, converter phase A and motor phase A, and phases el and 6 respectively converter phase B and motor phase B, desifnafting these on the drawing hv @Mil/ii, an GD, MB, respectively.

" which is if unil is ohteineci. 26 is the current in phase A and 27 is he cnrrenll in phase B, and, by referring to Jche diagram, it will be seen that, while. 'che ciniren' Q6 in phase ehind its Veil; i

'we EL, the currengl. in phase i) legs behind 2 ie voltage inoeor phase l5, lons leeds D" 'le voitege of converter phase 1.41, ii; 'will illus oe Hher lshe phase ce verter gives en output of leerling current ini. fr of legging current, Whereas the load or motor receif'es legging current as in the previous connections.

. Referring now'y abo Fig. l, l have shovvn an embodiment of my invention es applied to the eperebion of trvo quarter phase induction motors errangecl. so that either., independently, er both together, may be operated from e single phase converter, but 'will he il shove nnersool that, es l here expleii f iesireel ninnher oiphnses n lewin leed may he use/al. is scarce to which ce; nested QS) enel 30. 3i is i, phase con h induction motor having bhe source ci? supply., .Snielole sm f :incl he enployed fo isconiiec either motors from. she converter Ehe istie." in the source of snp ily. is will seen convei and in ies with similar phases of the motors, mehr phase A', which are iheinselves connecbed in parallel by n'ieens conductors 39renri 3'?. ,Another phase of l ne oi bhe phases of 'the converter,

one enel to conrlnccr 529 ene n" connector 110, Whicl 1ers, mofgnr end being c nnec'ecl so condncic-r/l is connected so :i snisehle poiny onconipen self/or winch is connecrecl across-gef.

sppplied from the source. le sv shen that converter phase it@ emi inv series with phase B of ii "ch nre `hei'nseives connececl in` parallel, enel lie@ interpolate in his l is njvolsnge of sniiehle phase ne eriierl. from she source, which rohege lf hnve'shoen as hein e* Wels of she sourceE 'lie @ses rfc-er phase A,

inse A, is connec; il so she source.

version or singlel phase ino e polyphase elcernntiz current, it 'will be understood.

thee Athe (niverx'zer, which have describerl ns one oiE 'che induction motor type, may be serecl np before its load. is put on in any of the Well, known ways for starting such polyphnse machines from n single phase source. :liter the converter is at its running snee it may loe operated es :i single phase machine and the local may then be connected to it in any suitable fashion. As shown in the figure, the converter is connecuecl to two motors. if ii, he desired te disconnect these, switches 38 will. 'ne openef. enel switch elfi: closefl., Ithus connecting winding or' the converser by e* ccnrlnclloi across conductors lThe congerter will chen he run- .liny or the Well known 'forms "lock between any of swiwhes and iv he employed if desired. nle have ilescrihccl e preferred einhofliinen er my invention, I do not limit myself so such embodiment but seek in the appenciefl claims to cover all embodiments which inni' he obvious to those skilled in the and lo nos depart, from the spirit of my tion.

1@nini ns new end desire to secure `nic r: of the Uniecl. States, is,- hinntion, s single phase source, s innslnting nevice, irphase conihese connected to n. phase device, incl Ineens for innl. phese circuit e volt-nge dil'eren veine from that of seid source, phase er having another phase cennecloecl 'e seid source and in series with another phi renslating device.

f seid er erpoint in ceinhinecion, e single phase source, :i polyphsse xrnnslsing device, n phase con verser h vi ai phase connected "ao :i phase of `Ihe device, and. Ineens for inerpoler ng ino seid phase circuit :i vol*- rliil'ervelue from 'that of seid source but nhese liere'wi'sli, seid phase conver'eer hn'vii L iether phase connected. ro the source end in series with another of the phases of 25h v n'oine isleing device.

Lon, e single phase source, e translating device, e phase converter having phase connecsecl to a phase oi", seid rzinsleing clevice, and Ineens for deriving from seid source enel interpoleting into ssicl phase circuit e voltage different in velue from ihn-i; oi seid sour e, seid converter heving snot'rher phase connected to seid source end in with another phase of i g (levies y si seien, e single plieselsonrce, e, rensle'ting; de rice, e pines converter heving a phase connected to a phase of saidv translating device, and means for deriving from said source'and interpolating into' said phase circuit voltage 'diferent in value from that of said source but in phase therewith, said converter having another phase connected to said source and in series with. anothei` phase of .said translating device.

Ao. In combination, a single phase source,

means for deriving a voitage therefrom pronoitionalto that of said soin-ce .L 9

a polyphase translating device,

and phase conveiter yERNST F. WALEXANDERSON.

Witnesses:

BENJAMIN HULL, MARGARET WooLLnL-f. 

